Used camper purchase, possible roof issue - please advise

My experience is that the roof deck has gotten wet and soft and the molding strip screws have nothing to bite into. Thus they pull out due to tension on the molding. I was able to carefully remove the molding/caulk; peel back the roof material and replace the back decking on my TT when this happened to me. If you're handy with tools, it's not too bad a job, though somewhat tedious to get everything re-caulked and water-tight.